1. Field of the Invention
The present disclosure relates to subject matter comprised of a light source and a modifier structurally related to the light source so as to modify light therefrom, particularly a light bulb cover made of a light pervious material.
2. Description of Related Art
Non-incandescent light bulbs such as compact fluorescent light bulbs (CFLs) and light-emitting diode bulbs (LEDs) are energy-efficient alternatives to conventional incandescent bulbs. In an incandescent light bulb, light is produced by using an electric current to heat a thin filament until it is white-hot and glows. The filament is protected from the atmosphere by a glass bulb that is evacuated or filled with inert gas, which produces a warm, soft, aesthetically pleasing light.
However, one significant disadvantage associated with a conventional incandescent light bulb is that it is not energy efficient. An incandescent bulb wastes a considerable amount of energy to create the heat that lights an incandescent bulb. On the other hand, in a CFL, electric current energizes a gas, such as argon and mercury vapor, which excites a coating inside the bulb. CFLs lose very little energy to heat, so they require significantly less electricity than conventional incandescent bulbs. In general, a CFL uses about 75 percent less electricity than an incandescent bulb with the same light output, while lasting about 10 times longer. Additionally, replacing incandescent bulbs with CFLs can reduce cooling costs since CFLs produce less heat. Similarly, LEDs use less electricity and produce less heat than conventional incandescent bulbs while also producing more light. As a result of the energy savings associated with non-incandescent light bulbs, many countries, including the United States, have enacted legislation to gradually phase-out and replace incandescent light bulbs with more energy efficient light bulbs.
Like incandescent bulbs, CFLs come in a variety of shapes. Popular designs include a helical design with visible fluorescent tubes arranged in a spiral as shown in FIG. 1A. Another popular design is a tubular design as shown in FIG. 1B. However, one drawback with tubular and helical CFL designs is that many people find these designs aesthetically unpleasing because their appearance is markedly dissimilar to that of the conventional incandescent bulb. In addition, CFLs are made of glass tubing and can break if dropped or handled roughly. This complicates their disposal because they contain mercury, which is classified as a hazardous material. Similarly, many people also find LEDs aesthetically unpleasing because its appearance also represents a significant departure from that of conventional incandescent bulbs.
Another shortcoming associated with CFLs and LEDs is that many people perceive the quality of light emitted by many non-incandescent bulbs as harsh or “cold” in comparison to the warm soft light emitted by a conventional incandescent bulb. This shortcoming is mainly attributed to non-incandescent bulbs having a higher Color Correlated Temperature (CCT) than their conventional incandescent bulb counterparts. The CCT measures in Kelvin (K) the appearance of the light itself—how “warm” or “cool” it seems. Higher CCT values correlate to cooler, bluish-white light, whereas, lower CCT values correlate to warmer light. Typically, a CCT range between 2700K-3000K is considered warm or soft white, about 3500K is considered white, bright white, or medium white, about 4100K is considered cool white (bluish-white) and about 5000K-6500K is considered daylight. As a result of the CCT range differences, many purchasers are reluctant to switch from conventional incandescent bulbs to CFLs and LEDs.
Another disadvantage of CFLs and LEDs is that these bulbs generally emit light from a smaller surface area than their conventional incandescent bulb counterparts. Current CFLs and LEDs create visual “hot spots”, which are bright spots in the field of view arising from light being emitted from a relatively small surface area. “Hot spots” are especially problematic for CFLs and LEDs that are typically visible such as the light bulbs on a vanity mirror fixture or bulbs on a chandelier type light fixture. Therefore, many consumers are hesitant about using CFLs and LEDs where the bulbs are likely to be in an observer's field of view.
Various solutions have been developed to enhance the appearance of non-incandescent light bulbs. One such example is a screw-on/slip-on plastic cover that is secured directly to the surface glass bulb of a CFL. Another example is a shade that attaches to the glass tube portion of a spiral shaped CFL. Another device includes a cover that includes two fingers that contact the glass tube portion of a spiral shaped CFL.
Although these covers enhance the overall appearance of a CFL, they present additional problems. Specifically, these covers increase the likelihood the glass tubing will break since the cover secures directly to the surface of the bulb, which is particularly undesirable since CFLs contain hazardous materials. Another disadvantage is that these covers cannot be reused with other CFLs. In other words, the cover must be designed specifically for each CFL bulb configuration and size. A further disadvantage, particularly with slip-on covers, is that many of the prior art covers have part-lines or seams, which may distort the light creating unsightly patterns, light intensity or color differences, and/or shadows when light is transmitted through the cover.
Additionally, some CFLs and LEDs are manufactured with hard plastic covers designed to resemble the shape of conventional bulbs. These covers screw onto the base of an existing non-incandescent light bulb. Although these covers in combination with a non-incandescent light bulb are more aesthetically pleasing, they also present additional problems. In particular, the base of the non-incandescent light bulb must be adapted to mate with the cover connection, i.e. the bulb must be manufactured with a threaded base configured to mate with the cover. As a result, these covets cannot be used with non-incandescent light bulbs without threaded bases, which presents a problem since a considerable amount of non-incandescent light bulbs are manufactured without threaded bases. Another disadvantage of these covers is they must be designed specifically for each CFL bulb configuration and size, and cannot be reused with other CFLs. A further disadvantage is that many of these covers are made of hard brittle material that can break easily, which introduces a potential safety issue. Additionally, they may discolor over time, which is not very aesthetically pleasing.
Accordingly, there remains a need in the art for more versatile cover for a non-incandescent light bulb that is aesthetically pleasing, flexible and seamless, capable of emitting light with a warm appearance and containing a broken tube and facilitating its disposal while also requiring no modifications to the bulb and capable of fitting a multitude of bulb configurations and sizes.